We built a large Thien separator for our shop planer and it works just great. Now I want to build one for use with our drum sander. This sander is responsible for rapidly clogging the HEPA filter on our new 5 HP Oneida Dust Gorilla cyclone. Is there an optimum slot width that I should use to collect the very fine sander dust? Chunks and larger pieces of wood are not an issue here. Also, has anyone built a smaller version of the Thien to fit a 30 gallon plastic barrel?